It uses satellite tracking data on 16 species of albatross and three petrel species, all endangered by commercial and pirate longline fishing fleets. These fleets use nets up to 130 kilometres long carrying thousands of baited hooks.

It identifies hot spots where both longliners and large numbers of seabirds are found in waters around New Zealand and southeast Australia, the southwest Indian Ocean, the south Atlantic and the north Pacific.

Conservationists say that fairly simple measures can be used by longliners to reduce seabird deaths.

"They can thaw out their bait, which will then sink faster and not attract birds, or they can attach weights to sink the bait," said BirdLife's Richard Thomas.

He said Brazilian fishermen use a colourful but effective technique that involves dying their bait two shades of blue.

Birds tend not to see blue but fish do. The first dye keeps the birds away but is water soluble and bleaches after the bait sinks.

This leaves a fat-soluble blue dye that makes the bait more attractive to fish, so both fishermen and birds win.

Slow breeders

Albatrosses are slow breeding, so there are fears that longliners are killing some species faster than they can reproduce.

All 21 albatross species are officially classed as under global threat of extinction.

The elegant white gliders are famed for their large wingspan and the long ocean journeys they make. The wandering albatross has a wingspan of nearly four metres, the broadest in the world.

The report also highlighted the huge distances travelled by some species during migration.

The northern royal albatross can fly up to 1800 kilometres in 24 hours and the grey-headed albatross can circle the globe in 42 days.